SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2062c8034ba21c6ce0ccf8f360e50e32e444b76cf876f48b59f20ef0e04893db' 
  AND token = 'g0pJZupyKvK79uxO2aCZwbV0isgB8StqLctRZ1tRH9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}